Many Orthopedic Trials Do Not Adhere to Principle for Validity

Many trials purporting to follow the intention-to-treat principle actually fail to do so

By Jeff Muise

HealthDay Reporter

FRIDAY, Sept. 4 (HealthDay News) -- Many orthopedic randomized clinical trials do not properly follow the intention-to-treat principle, potentially producing bias in trial results and analyses, according to a report in the Sept. 1 Journal of Bone & Joint Surgery.

Amir Herman, M.D., of Chaim Sheba Medical Center in Ramat-Gan, Israel, and colleagues reviewed eight orthopedic journals for the years 2005 to 2008 and identified articles on 274 clinical trials in orthopedics. The reviewers assessed the studies to determine if they observed the intention-to-treat principle, in which study results are analyzed depending on the subjects' original treatment cohort, regardless of treatment ultimately used. In particular, the reviewers assessed methods employed to account for missing data.

The researchers report that 96 of the 274 clinical trials claimed to employ the intention-to-treat principle, but adherence to the precise definition of the principle was found in just 45 of the 96. In 44 of the 96 trials, patients lost to follow-up were not included in the final analysis, in contravention of the intention-to-treat principle. The most conspicuous violation of the principle was in studies of surgical interventions, while the most common method of adjustment for missing data was the technique of "last observation carried forward."

"In most of the randomized clinical trials published in the orthopedic literature, the investigators did not adhere to the stringent use of the intention-to-treat principle, with the most conspicuous problem being a lack of accounting for patients lost to follow-up. This omission might introduce bias to orthopedic randomized clinical trials and their analysis," the authors write.